The PS4 will definitely outsell the Wii U lifetime in Japan. Even the Wii didn't do that much better than the PS3, outselling it by only 25% and falling, despite the PS3's early high initial price and lineup up into 2009, the Wii phenomenon coming very quickly, and the presence of Monster Hunter Tri on the Wii.
The real question is, when can the PS4 reach the Wii U, and how much higher will it get?
The Wii U's lifetime will not be much longer than the Wii's, suggesting that it will have few sales after 2018. It is also unlikely that third parties will suddenly flock to the Wii U, but considering how the first big 3rd party game for the Wii was 2009's Monster Hunter, that won't be the big loss. The problem will likely be that Nintendo's various new and returning series will not live up to Wii-era hits like Wii Fit and Sports.Not to mention the price and controller appeal.
That said, the Wii U seemingly has the advantage of being better supported for a longer period than the Wii did. Nintendo has shown quite a level of commitment to making software for the Wii U, including some of its biggest games ever and smaller budget titles like Rainbow Curse. Super Smash Bros and Mario Kart can keep some momentum in 2015 while games like titles like Xenoblade Chronicles X, Mario Party 10, Zelda U, Mario Maker, and Yoshi can keep the Wii U from plummeting too quickly. Not to mention that Nintendo's recent partnerships and workingws with the likes of Capcom and Koei Tecmo could bring more of their games to the system.
The PS4, meanwhile, might have problems reaching even the PS3's status. The PS3 has sold as much as it has in Japan because of some really big retail games not possible (or at least as spectacular) on the Wii or handhelds. These big hit included Final Fantasy, Resident Evil, Warriors, Metal Gear Solid, Tales of, Yakuza, and Call of Duty. Note that these are mostly franchises that existed prior to the PS3, though games like GTA and CoD did become much more popular during this time. Unfortunately for the PS4 though, it appears that some of these series will not help as much this time around.
The big problem is Final Fantasy. FF15 will likely be released in late 2015 or early 2016, based on how Square Enix is finally being a bit more solid with the game's existence. This will be a bit earlier than the PS4 took to get a Final Fantasy. However, Final Fantasy is not as big a brand as it was in 2009. Comparing the sales of FFX and FFX-2 to FFXIII, XIII-2, and Lighting Returns suggests that people were burnt by the series last gen. Even if FF15 is the best numbered entry since the PS2, it has to work its way uphill. Meanwhile, Square Enix also has Kingdom Hearts and Dragon Quest, but those are not getting numbered iterations for a little while, even if DG11 is for the PS4. KH3 will not come out within a year of FF15 due to the overlapping resource consumption. Dragon Quest 9 and 10 were announced three and four years before release, so the lack of word about DQ11 means that it is probably not coming out any sooner than 2018 or so.
As for other big games, Metal Gear Solid shifted towards the PSP last gen in Japan, especially with Peace Walker. Resident Evil 7 will sell well in Japan, but Capcom's financial problems will slow that series down a bit. The Tales of series is not exactly leaping into the next gen, seeing how Zesteria was just released for the PS3. Yakuza is split between gens, slowing down adoption for now. Ironically, only Grand Theft Auto and Call of Duty have no immediate problems, but even now, those will not be THAT big in Japan.
My guess: the PS4 surpasses the Wii U in early 2016, with the Wii U selling 5 million lifetime and the PS4 selling 9 million lifetime.
